All that remains of the Cathedral of St. Paul is one wall, now called the Ruins of St. Paul's (or Ruínas de São Paulo in Portuguese). The carvings on the remaining facade were done by Japanese Christians living in exile in Macau and local artisans under the direction of an Italian Jesuit priest.
The cathedral, built in 1580 on a hill, was burned not once, but twice. The building underwent reconstruction in 1602 after the second fire. Construction was finished in 1637 and at the time, the Cathedral of St. Paul was the largest Catholic church in all of Asia. But as the old saying goes, third time's a charm. In 1835, a typhoon hit Macau and yet another fire destroyed the cathedral. Sadly, the church was never rebuilt.
The ruins, including the crypts, were excavated in 1990 and 1995. The facade was reinforced with concrete and steel to make it safe while still retaining the original appearance. You can climb up a flight of stairs behind the facade and enjoy the view out of the three windows in the remaining wall.
The ruins are really beautiful and my photos don't quite capture the massive size of the remaining wall. It must have been a commanding sight to see such a big church at the top of the hill.
Some souvenirs on the Rua de São Paulo
Walking up the Rua de São Paulo to get to the ruins. It was a bit crowded.